Production of permanently sculptured pile fabrics

ABSTRACT

DEEP SCULPTURING PILE FIBERS, E.G., ACRYLIC AND POLYESTER, BY DEPOSITING POLAR SOLVENT CONTAINING SOLUTIONS FOR THE FIBER IN THE PILE, E.G., DIMETHYL FORMAMIDE, DIMETHYL SULFOXIDE, HAVING A VISCOSITY OF 500 TO 1000 CPS.

P. MILLER 3,

' PRODUCTION OF PERMANENTLY SCULPTURED FILE FABRICS March 2, 1971 Filed May 12, 1967 E Q Q4 o fi oeo INVENTOR. PhH/p M/Y/E'f Afforn ey United States Patent 3,567,548 PRODUCTION OF PERMANENTLY SCULPTURED PILE FABRICS Phillip Miller, 4 Redwood Road, Norwalk, Conn. 06850 Filed May 12, 1967, Ser. No. 639,927 Int. Cl. D03c 19/00 US. Cl. 156277 12 Claims ABSTRACT OF THE DISCLOSURE Deep sculpturing pile fibers, e.g., acrylic and polyester, by depositing polar solvent containing solutions for the fiber in the pile, e.g., dimethyl formamide, dimethyl sulfoxide, having a viscosity of 500 to 1000 cps.

Pile fabrics have achieved a Wide degree of public acceptance due in particular to their luxurious hand, appearance and Warmth. An important factor which has however inhibited even greater demand for pile fabrics has been the lack of a wide selection of designs, particularly in multicolored patterns, as compared to the variety available in other fabric constructions. The art has experienced great difficulty in producing interesting, deep, clearly delineated and reproducible designs in an inexpensive manner. Hence low-cost pile fabrics have tended to be esthetically monotonous.

It is an object of this invention to provide a method for decorating pile fabrics in a wide variety of contours, contrasts, multicolored patterns, and combinations thereof. As a further object this decoration should be easily controllable and reproducible. As an additional object, this method should be simple and inexpensive and without damage to the fabric. Furthermore such ornamentation should be capable of withstanding normal use and cleaning operations.

To this end, several methods have been suggested by other workers in the art but each has, to the best of my knowledge, been seriously lacking in one or more respects. in my copending application Ser. No. 638,704, I disclose a method for producing ornamented pile fabrics in which the ornamentation is effected solely by the adhesive action of an applied adhesive solution. While the decorated pile fabric produced in this manner is attractive, it is difficult thereby to deeply contour a complex design. Furthermore its total resistance to dry-cleaning is highly dependent on thorough crosslinking. It is thus a further object of this invention to provide a simple method for deeply con touring even complex designs. It is a still further object that this contouring be permanent to dry-cleaning and other deleterious environmental factors and that its retention be not dependent solely upon an external adhesive.

I have now discovered a process that can meet all these objects. This process broadly comprises (1) directly depositing in a predetermined pattern a solution having a viscosity of about 500 to 1000 cps. and containing a solvent for at least one of the major constituent fibers of said pile, said deposition being at a depth of about to 30% of the average pile height and in sufficient amount and under sufficient pressure as to cause the solution to penetrate substantially to the base of the pile with essentially no lateral flow, (2) heating said solvent-containing pile fabric to remove at least 75% of the solvent, (3) compacting said pile and (4) relofting the pile elements. If desired, metallic particles can be included in the deposited solution.

The sculptured effect as thereby produced is truly permanent since part of the pile itself has actually been dissolved. In other words, ornamentation is achieved and maintained by chemical etching and not merely by adhesive action. Hence dry-cleaning or any other deleterious conditions cannot destroy the pattern definition.

Suitable solvents for the practice of this invention are dimethyl formamide, dimethyl acetaniide, tetramethylene sulfone, dimethyl sulfoxide and similar highly polar solvents.

The viscosity of the solution can be increased to within the range of 500 to 1000 cps. by the addition of silica thickening agents or similar thickening materials well known to the skilled chemist. 'If the viscosity is significantly lower than 500 cps, the solution tends to laterally flow thus resulting in a smudged unesthetic design. On the other hand, if the viscosity is significantly above 1000 cps. the solution cannot easily penetrate to the base of the fiber with the result that the sculpture will be of only limited depth. Within the aforesaid critical range, the optimum viscosity is a function of the speed of operation, the drying time and the specific materials and apparatus employed.

The amount of solution deposited and the pressure of deposition should be correlated so that the solution penetrates substantially to the base of the pile with essentially no lateral flow. These optimum absolute values will vary with the specific apparatus, solution and fabric employed. With most pile fabrics the amount deposited should be within the range of O.82 gallons/ sq. yards of printed space and the pressure should be within the range of about 40 to 100 p.s.i.

The solution is deposited by means of an engraved roll as distinct from a heated embossing roll. With pile fabrics having pile projections 0.1 to 0.5 inch, the engraving need only be on the order of 0.010 to 0.040 inch deep.

If the pile fabric contains a high percentage of fibers which are readily soluble in the chosen polar solvent, one need heat the solvent-treated fabric only to the degree necessary to remove the solvent. The pile can then be cold compacted and relofted. Exemplary of such piles are those containing acrylics and cellulose acetate. For still deeper effects, the compacting can be effected in a heated zone such as a hot nip. Pile fabrics which contain only fibers such as polyester which are not readily soluble at room temperature in such polar solvents should be compacted in a heated zone such as a hot nip at a temperature above which the fibers become soluble in the solvent.

In specific embodiments of this invention, the solvent solution may also contain a compatible adhesive material soluble in said solvent which is curable and which can be rendered partially heat settable. Particularly advantageous results have been obtained using adhesive formulations based on polyurethanes. Other curable adhesive formulations based on urea-formaldehyde, phenolics, acrylics, curable epoxy resins and others well known to those skilled in the adhesive art are also utilizable and aid in maintaining pattern definition during dry-cleaning. Par-- ticularly with suitable plasticizers well known in the art, such added adhesives increase the flexibility and elasticity of the decorated pile fabric. When the pile is composed of a blend of soluble and insoluble fibers, the adhesive should be one that has sufficient tack and cohesiveness to hold the insoluble fibers in a matted condition as it exits from the squeeze rolls.

In one embodiment of the above method, the pile fabric is fed through a printing apparatus containing one or more engraved rolls inked with the adhesive-solvent solution which can be colored or colorless. The solution is deposited thereon beneath the pile surface in accordance with the engraved design. The engraved roll itself penetrates the pile only to a depth of about 10 to 30% of the average pile height. The printed pile fabric is then rendered at least partially .settable by any suitable means, as for example, heating to about F. The fabric is then sent to a pressure device to compress the entire pile. The compacted pile fabric is then cured by any of a variety of means and then subjected to finishing treatment which relofts the pile. The resulting fabric has a controlled, sharply defined permanent pattern in three dimensions while retaining the flexibility and other desirous properties of a pile fabric. The ornamentation is not affected by commercial dry-cleaning.

The setting operation may involve cross-linking for retention of the adhesive during dry-cleaning but it is not critical to this invention that the adhesive be cross-linked. Cross-linking can be accomplished in numerous Ways Well known in the adhesive art, the choices being largely de pendent on the nature of the adhesive. For example, chemical cross-linking can be accomplished by the passage of time, chemical treatment, radiation, application of heat or pressure or the like depending on the chemistry of the adhesive.

As a means of future understanding the invention, reference is made to the figure exemplifying a specific embodiment of this invention. The figure is a diagrammatic showing of the apparatus utilized according to the specific embodiment.

The following three examples illustrates the operation of this embodiment.

Example I A pile fabric, a A inch deep polyester pile having a cotton backing, is decorated in a four color pattern in the following manner.

The pile fabric 2 is fed from a supply roller '1 on through the four nips between engraved rolls 3, 4, 5 and 6 and back-up rolls 7, 8, 9 and 10, respectively. Each engraved roll is 5 inches in diameter with a Width of 60 inches and the engravings are .035 inch deep. The printing pressure on each cylinder is provided by two air cylinders (not shown) having 6 inch diameters supplying 80 to 100 lbs. of pressure per square inch. Each cylinder drives one' end of the engraved roll against the corresponding rubber back-up roll. En'graved roll 3 is inked by a colored adhesive solution 11 picked up from color box 12 applied by a doctor blade 13. The other engraved rolls are similarly inked with different colors (not numbered).

The colored solutions contain suitable dyes dissolved in dimethylformamide. Enough Cab-O-Sil (a colloidal silica preparation-Cabot) is added to increase the viscosity to 750 cps. Each engraved roll then prints its portion of the total design of the pile fabric. The engraving rolls are synchronized and adjustable to ensure perfect register so that there is no color mixing on the pile fabric. Hot air ducts 14, 1'5 and 16 partially dry the fabric between the rolls to prevent marking off onto the next roll. No back gray cloth is necessary as the pile backing serves sufficiently as a cushion to produce sharp designs.

[The printed pile fabric then passes up over guide roll 17 and onto a conveyer belt 18 moved along by a series of idle rolls 21 into a heated tunnel 19. The oven 20 heats the tunnel and fabric to a temperature of about 150 F. to 300 F., removing about 80% of the solvent from the printed colored solution. Heated air is continuously supplied to the oven at 22 and exhausted at 23 carrying away the vaporized solvent.

The fabric then exits from the tunnel and is passed to a pair of hot squeeze rolls 24 and 25 having a nip therebetween small enough to cause all the pile projections to mat down firmly against the backing. The surface temperature on the pressure roll 24 should be about 212 F. The pressure rolls should preferably be covered with Teflon or other release agents to minimize sticking.

After the fabric emerges from hot roll 24 and rubber roll 25, it passes through the cold nip between roll 25 and roll 26 to cold set the decoration. The fabric is then passed to wind-up mechanism 28 over conveyer 27 and thereafter can be subjected to a normal finishing treatment. For example the pile fabric can be subjected to the .4 action of steam jets and mechanical brushing in the conventional manner or with hot air and heat. The full loft returns to the unprinted areas of the pile fabric while the printed areas remain depressed according to the predetermined design. Surprisingly I have found that about 10 to 25% of the solvent can remain on the pile fabric while subjecting to the compacting step and during compression in the hot nip the residual solvent can be flashed olf without any loss of pattern. The overall effect is a luxurious, permanent three-dimensional multicolored design.

Example II The same pile fabric as in Example I is processed in the same manner. The printing solution contains an adhesive and plasticizer and has the following composition in addition to the various pigments:

Parts by weight Daltofier 15 polyester resin (I.C.I.) 33 RC-805 isocyanate resin (Du Pont) 5 U148 plasticizer (Rohm & Haas) 10 Dimethyl formamide 150 A pile fabric having 4 inch acrylic pile on a cotton backing is treated as above. The printing solution has the following composition:

Parts by Weight Daltoflex 18 polyester resin 33 -RC805 isocyanate resin 5 Dimethyl sulfoxide 70 Enough Cab-O-Sil is added to give a viscosity of 750 cps. The processing is the same as in Example I except that roll 24 is at 60 F. No further compacting was employed. After curing, in air for 24 hours, the pile fabric has an attractive, permanent, sculptured effect and is flexible and elastic.

In a still further embodiment, multiple level effects can be achieved by using several engraved rolls varying in the depth of their engravings. For example, one can produce by the method of this invention a pile fabric having a surface rose print with a deeply incised outline. A variable height effect can also be achieved herein by the selection of the design so that as the straight pile tips are folded over in going through the various nips they essentially cause the pile to lay flat. For example, if one selects a design in which the lines are inch apart and the pile is about the same length, much of the fiber length will be held in a plane position. That part of the design which is greater will permit the full length of the pile to become erect.

The color in the printing compositions can be imparted by conventional dyes, inks, pigments, lacquers and combinations thereof, and in general, any suitable colorant which is compatible with the adhesive composition.

Virtually any design is obtainable in any array of colors by the method of this invention. The instant invention has the further advantage over general embossing methods which employ heated cameo type pressure embossing rolls in that the latter are considerably more expensive, on the order of ten times as much, as photoengraved printing rolls. The relief on the hot pressure embossing roll, which'is hot enough to soften the fiber, must be deeper than the pile to avoid melting the fiber. On the other hand, by the method of this invention, much shallower engravings are possible since the solution is made to penetrate the pile by pressure or capillary flow.

The printing apparatus shown in the figure is of course merely illustrative and numerous other such apparatus can be employed for the purpose of this invention, For example, the pile fabric can move around a cylinder instead of an a belt with the printing rolls disposed along the cylinder circumference.

Other additives can be incorporated into the printing composition to impart other desired properties, said additives being so chosen of course, as not to adversely affect the printing step or the adhesive action. Thus, for example, conventional fire-retardant, anti-static, bacteriostatic, ultraviolet stabilizer and similar additives can be applied to the pile fabric in accordance with the method of this invention without requiring additional processing steps. For example, because of the nature of the deep and wide engraving employed in the method of this invention, one can incorporate metallic particles of appropriate size in the printing solution to product glitter effects.

Numerous other variants of the above-described process will be apparent to one skilled in the art within the spirit of the present invention.

What is claimed is:

1. A process for sculpturing a pile fabric comprising the steps of (1) directly depositing in a predetermined pattern on the surface of said pile a solution having a viscosity of about 500 to 1000 cps. and containing a solvent for at least one of the major constituent fibers of said pile, said deposition being at a depth of about to 30% of the average pile height and in sufi'icient amount and under suflicient pressure to penetrate the pile substantially to the base of the fabric, (2) heating said solvent-containing pile fabric to remove at least 75% of said solvent to form in situ an adhesive mixture comprising the dissolved major constituent fibers of said pile, (3) compacting said pile with said adhesive mixture present and (4) relofting the pile elements.

2. A process according to claim 1 wherein one of the major constituent fibers of said pile is selected from the group consisting of acrylic and cellulose acetate fibers.

3. A process according to claim 1 wherein said pile is comprised mainly of polyester fiber.

4. A process according to claim 1 wherein step (3);

6 comprises compacting at a low temperature not substantially greater than room temperature.

5. A process according to claim 1 wherein said compacting step (3) is conducted at a temperature above that necessary to solubilize the pile fiber in said solvent solution.

6. A process according to claim 1 wherein said solvent is selected from the group consisting of dimethyl formamide and dimethyl sulfoxide.

7. A process according to claim 1 wherein the deposited solution also contains a curable adhesive and wherein after step (4) the adhesive is cured.

8. A process according to claim 1 wherein the deposition of step (1) is conducted sequentially with a multiplicity of said solutions.

9. A process according to claim 1 wherein the deposited solution is colored.

10. A process according to claim 8 wherein at least two of said sequentially deposited solutions differ in color.

11. A process according to claim 8 in which at least two of said sequential depositions vary in the depth of deposition.

12. A process according to claim 1 wherein said deposited solution contains metallic particles.

References Cited UNITED STATES PATENTS 1,955,582 4/1934 Golding 2876T 2,069,760 2/ 1937 Hueller 2876T 2,267,790 12/1941 Dickie et a1. 2876T 3,096,561 7/ 1963 McNally et a1. 2872P 3,399,070 8/1968 Schurf 117-72 FOREIGN PATENTS 1,026,960 4/1966 Great Britain 2876 CARL D. QUARFORTH, Primary Examiner F. M. GITTES, Assistant Examiner US. Cl. X.R. 

